At various stages in manufacturing electronic assemblies, electric components and the electronic wiring boards on which they are mounted must be cleaned. For example, when forming a soldered joint, solder is placed on a board at locations where component leads are to be coupled to a printed circuit. An acidic flux is typically applied to the solder before fixing the leads thereto in order to clean oxides and otherwise prepare the solder. After the leads are fixed to the solder the flux must be cleaned from the board.
The boards may be passed through assembly line cleaners in which all components and the entire board are cleaned to remove solder joint flux residues and other ionic and nonionic contaminants. At other times, such as in repairing a board or in implementing an engineering change, it is necessary to clean just a local area of the board such as around the soldered joints of a component on the board. Conventionally, both in-line and localized cleaning processes utilize CFC solvents such as 111 trichlorethane. However, because CFCs have been found to be damaging to the environment, they are being replaced, at least in the in-line systems, with aqueous based cleaning solutions, specifically saponifiers mixed in water. To date, although aqueous systems have been developed for in-line cleaning processes, CFCs are still used in localized cleaning. Typically, the CFCs are simply sprayed on local areas.